Notes

Seven months earlier, on October 3, 1981, Mancini fought Alexis Arguello for the WBC Lightweight Championship and was stopped in fourteen rounds.

Mancini entered the fight against Frias ranked No. 3 by the WBA.

While Mancini was training for the Frias fight in Tuscon, Arizona, the police got a call from a chambermaid who worked at the hotel where Mancini was staying and were told that three men with guns showed up at the hotel looking for Mancini. The men asked the chambermaid for the location of Mancini's room, and she pretended not to know. The men then got in a car and left. When Mancini learned of the incident, he moved his training camp to Las Vegas, Nevada, and trained with police surveillance until the fight. Neither the aim nor identifies of the men were ever discovered.

Less than thirty seconds into the fight, during an exchange in the center of the ring, Frias staggered Mancini with a left hook to the chin. Frias moved in for the finish, and the two furiously traded punches. Mancini suffered a cut on his left eyelid, and Frias was cut under his left eye. With less than a minute remaining in the round, Mancini wobbled Frias with a left hook. He followed up with a barrage of punches and dropped the champion with another left hook. After Frias rose and took the mandatory eight-count, Mancini backed him to the ropes and battered him until the referee stopped the fight. The time of the stoppage was 2:54. It was one of the most spectacular first rounds in boxing history.